Rupture of vulnerable plaques is the main cause of acute coronary syndromes. Identification of such plaques is therefore essential to develop treatment modalities to stabilize them. Several intravascular technologies are described in this review. The ideal technique would provide morphological, mechanical, and biochemical information; although several imaging techniques are currently under development, none of them provides, alone, such all-embracing assessment. Optical coherence tomography has the advantage of high resolution, thermography has the potential to measure metabolism, and Raman spectroscopy obtains information on chemical components. Intravascular ultrasound (IVUS) and IVUS-palpography are easy to perform, and assess morphology and mechanical instability. Shear stress is an important mechanical parameter that deeply influences vascular biology. Nevertheless, at present, each technique generally only assesses one clinical feature, so that none of them can unequivocally and comprehensively identify a vulnerable plaque nor predict its further development. Thus, the combination of several modalities is required to ensure high sensitivity and specificity in detecting vulnerable plaques...